The hypothesis is that potentially patients with sickle cell disease may have sleep apnea. One causal scenario is that repeated splenic infarcts causing autosplenectomy leading to "compensatory hypertrophy" of tonsils and adenoids, results in increased incidence of obstructive sleep apnea. The increased obstructive sleep apena leads to hypoxemia which would be more severe in sickle patients with right shifted hemoglobin/oxygen dissociation curves. The hypoxia would exacerbate sickling and increase painful crisis and acute chest syndrome. Potentially there may be a link between having obstructive apena and disease severity. These findings could affect patient management and be used for more aggressive ascertainment of obstructive apnea in sickle cell patients.